Barthel's semifinal opponent on Saturday will be Belgian Kirsten Flipkens, who was leading Anna Tatishvili 6-2, 3-0 when the Georgian retired from their bout. Flipkens upset top seed Dominika Cibulkova in the opening round.

In the night matches, eighth-seeded Lucie Hradecka and Kristina Mladenovic were both winners to set up the other semifinal match.

Hradecka of the Czech Republic took down American Lauren Davis 6-4, 6-2 while Mladenovic of France had an easy 6-0, 6-1 win against American Melanie Oudin.